Found this deal at Costco Moorabbin. Still 1/2 pallet was left at around 4:30PM. Price decrease is not highlighted which is why it seems many people didn't notice. Next to it different washing power from Omo is stocked and that is $49.99. This pack also used to be that price in past.
It seems like Costco silently dropped pricing on some of the laundry/cleaning products (may be clearing stock or silent promo). Personally we really like this product. Since we bought it for the first time, we stopped buying NapiSan or SARD. This product does a really good job for coloured and white clothes. It was originally priced at around $35 at Costco and Amazon when it was introduced in Australian market.
Amazon is selling at $23 as of today (without S&S)